1. Field of the Invention
The present invention relates to a lithography system and a manufacturing method of commodities.
2. Description of the Related Art
An imprint apparatus cures a resin (imprint material) on a substrate (a silicon wafer or a glass plate) while a mold (original) having a pattern (fine structure) is pressed against the resin, thereby transferring the pattern of the mold onto the substrate, using the imprint technology.
In such a lithography apparatus, alignment between an original and a substrate is of prime importance. When the process rule stipulates a feature size of, for example, 100 nm or less, the range of the error (tolerance) of alignment between an original and a substrate tolerated by a lithography apparatus is about several to several ten nanometers.
Also, a lithography apparatus, especially an imprint apparatus, is required to improve the transfer accuracy and the transfer rate. Compared to an exposure apparatus, an imprint apparatus generally costs less per unit but requires a longer process time (that is, has a lower transfer rate), and therefore has a lower throughput. Hence, in recent years, a stage for positioning (moving) a substrate is speeded up, and a cluster configuration formed by installing a plurality of imprint apparatuses in a semiconductor manufacturing plant is under development.
On the other hand, improvements in transfer rate and transfer accuracy generally have a trade-off relationship. For example, a stage speed-up increases the magnitude of a reaction force generated by a stage, and this vibrates not only an apparatus including the stage but also apparatuses arranged around it. Especially in the cluster configuration, even if one apparatus generates vibration only in a small amount, vibrations (phase and direction components) generated in a plurality of apparatuses are superposed on each other and therefore amplify each other, so the entire floor on which the apparatuses are installed may vibrate.
In bringing a mold into contact with a resin on a substrate (that is, pressing the mold against the resin) in an imprint apparatus, the positional relationship between the original and the substrate is maintained with high accuracy by alignment performed in advance. However, if vibration is transmitted from the floor to the apparatus, the positional relationship between the original and the substrate deviates, thus degrading the transfer accuracy. Although an expensive exposure apparatus can damp vibration, which, if undamped, is transmitted to the outside, using a counter mass to prevent it from being transmitted to any surrounding apparatuses, it is desired to minimize the use of a counter mass in an imprint apparatus advantageous in cost and footprint.
Under the circumstances, Japanese Patent Laid-Open No. 5-234865 proposes a technique of moving stages of two lithography apparatuses in synchronism with each other so as to mutually cancel reaction forces generated by the respective lithography apparatuses. In the technique described in Japanese Patent Laid-Open No. 5-234865, the stages of the respective lithography apparatuses are moved in synchronism with each other so that their acceleration (or deceleration) start time instants coincide with each other, and their impulses of the acceleration times (or deceleration times) and the accelerations (or decelerations) are equal in absolute value and opposite in sign. In this manner, the technique described in Japanese Patent Laid-Open No. 5-234865 employs the technical idea of a counter mass which cancels a force generated by one of two apparatuses by applying an opposite force from the other.
However, upon application of the technique described in Japanese Patent Laid-Open No. 5-234865 to an actual lithography apparatus, when one apparatus stops its operation upon a breakdown or in maintenance, the other apparatus must inevitably stop its operation even if this is possible in practice, because no apparatus which functions as a counter mass is present. This increases the number of apparatuses which must stop their operations in the cluster configuration, thus lowering the overall operating ratio.
Also, to actually set the impulses of the two apparatuses equal, it is necessary to additionally take into account, for example, the number of apparatuses, the positions at which they are installed, and the frequency components of vibration generated in each apparatus. It is therefore very difficult and impractical to set the impulses of the two apparatuses equal so as not to influence other apparatuses.